v4l2bufferpool: Use unique name for v4l2bufferpool object

Assign unique sequence number to an object name for better debugging

sys/v4l2/gstv4l2bufferpool.c

@@ -1669,8 +1669,9 @@ gst_v4l2_buffer_pool_new (GstV4l2Object * obj, GstCaps * caps)
 
   /* setting a significant unique name */
   parent_name = gst_object_get_name (GST_OBJECT (obj->element));
-  name = g_strconcat (parent_name, ":", "pool:",
-      V4L2_TYPE_IS_OUTPUT (obj->type) ? "sink" : "src", NULL);
+  name = g_strdup_printf ("%s:pool%u:%s",
+      parent_name, obj->pool_seq++,
+      V4L2_TYPE_IS_OUTPUT (obj->type) ? "sink" : "src");
   g_free (parent_name);
 
   pool = (GstV4l2BufferPool *) g_object_new (GST_TYPE_V4L2_BUFFER_POOL,

sys/v4l2/gstv4l2object.h

@@ -168,6 +168,8 @@ struct _GstV4l2Object {
 
   /* optional pool */
   GstBufferPool *pool;
+  /* the sequence of pool to identify (for debugging) */
+  guint pool_seq;
 
   /* the video device's capabilities */
   struct v4l2_capability vcap;